Brake system for automotive vehicles



Aug. 23, 1932 C. s, BRAGG vE1' AL 1,372,659l

BRAKE SYSTEM FOR AUTOMOTIVE VEHICLE-S Filed May 25, `19,28 :5Sheets-sheet 1 Aug- 23, 1.932 c. s. BRAGG ET ,AL 1,872,659

BRAKE SYSTEM FOR AUTOMOTIVE VEHICLES Filed May 25, 1928 5 Sheets-Sheet 2I 10 1N VEN TOR.

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BRAKE SYSTEM FOR AUTOMOTIVE VEHICLES Patented Aug. v23, 1932 UNITEDsTATEsPA-TENT ori-rcs CALEB S. IBRAGG, OF PALM BEACH, FLORIDA, lANDVICTOR W. KLIESRATH, OF PORT vWASHINGTON, NEW YORK, ASSIGNORS TOBRAGG-KLIESRATH CORPORATION, OF

LONG ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK l' BRAKE SYSTEMFOR AUTOMOTIVE VEHICLES 'l .Application led May 25, 1928. Serial No.280,424.

Our inventionl consists in the novel features hereinafter described,reference beingv had to the accompanying drawings which show severalvembodiments of the invention selected by us for purposes ofillustration,

and the said invention is fully disclosed in the following descriptionand claims.

Our invention relates to vacuum brake mechanism for automobiles in whichthe brake mechanisms are applied by a power actuator A ployed to propelthe vehicle, or vehicles, and

atmospheric or higher iluid pressure. Where atmospheric pressure isemployed asythe higher fluid pressure, there yis a substantiallyconstant maximum pressure of approximately 10 pounds per square inch atsea level available for the operation ofthe actuator,

which maximum degree of rarication being obtained in the suctionlpassage when the throttle valve is closed or nearly closed, (the properposition for the throttle valve when the brakes are to be applied).

The amount of braking force which can be applied tothe wheels ofa'vehicle without locking the wheels willnecessarily vary in accordancewith-Variations in the coeiiicient of friction between the wheels andthe roadway, and these variations are chiefly'due to variations in thecondition of the road surface, due to moisture, ice, etc., and tovariations in the load supported by the wheels. Obviously it is mostundesirable t'o apply at any time sufficient Ybraking force to lock thewheels, as thiswill cause skidding, and in the case of four wheel-brakes applied to both steering and non-steering wheels, the ,lockingof steeringwlieels deprives the operator of all control of the directionof movement of lthe vehicle, which he canv recoveronlyA by releasing allthe brakes. v

The object of our present invention is to provide a pressure regulatingvalve mccha- "nism-'or mechanisms for controlling'the maxi mum powerapplication of the brakes independent of the controlling valve mechanismnormally used for the application of the brakes, said pressureregulating valve being located between the actuator or actuators and thecontrolling valve mechanism therefor,

where the actuator piston is maintained submerged in the higher fluidpressure or atmosphere when in released position, or between theactuator cylinder and a connection with the suction passage independentof the controlling valve mechanism where the actuator piston ismaintained submerged in vacuum when in the released position, the sameform of valve mechanism being adapted to both locations, said pressureregulating valve be ing constructed to maintain a predetermined degreeof rarication available for the operation of the actuator or actuators,and therefore a predetermined available differential of fluid pressures,the air pressure being subn stantially constant, fand said valvemechanism being readily adjustable to vary the available degree ofrarifcation and therefore the differential of pressures to bemaintained. We construct the power actuator, or actuators, and theconnections therefrom to the brake mechanismactuated thereby in suchymanner that the wheels cannot ordinarily be locked by an application ofthe maximum power of the actuator or actuators when the wheels are uponaverage dry roadway and the vehicle wheels are under a' predetermined.

load condition of the vehicle, for example Y when fully loaded, underwhich conditions thev operator can apply the brakes withV the fullpewerof the actuator.without` danger of skidding. When the vehicle islightly loaded or when passing over roadway which is wet, or muddy, orcovered with ice or when ever the coefficient of friction between theywheels andthe roadway is otherwise decreased, the pressure regulatinvalve or valves may' be quickly adjuste by means within easyreach of thedriver, so as to proa vide such reduced v"degree of r-arification,available 'to the actuator as will permit thel actuator to be operatedwith maximum force without locking the wheels. The brakes may thereforebe fully applied by power, by the operator operated controlling valvemechanism without material danger of skidding under all variations ofroad or load conditions. The operator operated part for the brakeapplying valve mechanism is preferably connected with certain of thebrake mechanisms, so that should greater power be needed for emergencyapplication of the brakes, under any adjustment of the pressureregulating valve mechanism, the physical force of the operator may beapplied to the connected wheel brake mechanisms only, and these brakemechanisms can also be applied by physical force alonein case of failureof power.

Our invention also comprises certain novel features of construction andcombination of parts hereinafter described and particularly pointed outin the following description and claims.

In the accompanyingr drawings,

Fig. 1 is a diagrammatic View representing a tractor and trailerequipped with a vacuum brake system embodying our present'invention, theactuators having their pistons maintained submerged in atmosphere whenin retracted position.

Fig. 1a is a fragmentary view, similar in general to the system of Fig.1, but disclosing a plurality of actuators for the trailer brakes, eachactuator serving to operate a separate set of brakes on the trailer.

Fig. 2 is'an enlarged sectional view of one form of the adjustablepressure regulating valve shown in Fig. 1.

Fig. 2a is a front view of the adjustin mechanism shown in Fig. 2.`-

Fig. 3 is an enlarged detail view of one g valve for the actuator,

form of controllin shown in Fig. 1.

Fig. 4 is a sectional view similar to Fig. 2, showing another form ofthe pressure regulating valve.

Fig. 5 is a view similar to Fig. 1, showing our invention embodied in abrake system in whichthe pistons of the power actuators are maintainedsubmerged in vacuum when in released position.

Fig. 5ais a detail of a part of Fig. 5 showing a slight modification.

Fig. 6 is an enlarged sectional view of a controlling valve mechanismsuitable for the installation shown in Fig. 5.

In Fig.`1 we have shown our invention embodied in a brake system for atractor indicated diagrammatically by dotted lines at A, and a trailerindicated by dotted lines at B, but the invention is not limited to thenumber of vehicles upon which it may be installed. C, C, represent thesteering wheel brake mechanisms and D, D, 'the non-steering wheel brakemechanisms of the tractor, A, and E,` E, represent brake mechanisms fortrailer B. Thebra'ke mechanisms may be of any preferred construction. Asshown each consists of a drum, 70, band, 71, and lever,

72, provided with the usual retracting spring,

73. The brake levers for the steering wheel brake mechanisms of thetractor are here shown connected to a rock shaft, v7 6, by links, 74,and arms, 75, the non-steering brake mechanisms being similarlyconnected by links, 74a, and arms, 7 5, to a rock shaft, 7 6a, and thetrailer brake mechanisms are similarly connected by'links, 74h, andarms, 7 5b, with a rock shaft, 7 6b, on the trailer. The tractor isshown in this instance provided with a power actuator comprising acylinder, 1, closed at its forward end and open at its rear end, andprovided with a piston, both cylinder and piston being movable withrespect to the tractor as shown in our former application for LettersPatent of the United States filed Oct. 8, 1927, Serial No. 224,841, butthis construction is not essential. The cylinder, 1, is shown pivotallysupported'on arms, 77, connected with the rock shaft,v 76, while thepiston, 3, is connected with an arm, 77a, on

. the rock shaft, 76a, so that a power stroke of the actuator causes,the piston and cylinderA to move toward each other and apply all of thebrake mechanisms, C, C, D, D. The capacity of the actuator and theleverages of its connections with the brake mechanisms are preferablysuch that thev wheels cannot be locked by the maximum power of theactuator, when the wheels are upon ordinary dry roadway and the vehicleloaded.

60 represents an internal combustion en-v ginemounted on Lthe tractorand provided with a suction passage comprising the intake manifold, 61,and a vertical'portion, 62, lead- Y ing from the carburetor, 63, to themanifold, and provided with the usual throttle valve, 64.

The actuator on the tractor is provided with a controlling valvemechanism which in this particular drawing is located eXteriorly of theactuator for connecting the cylinder, 1, between its closed end and thepiston, 3, with the atmosphere and with the suction passage between ,thethrottle valve, 64, and the engine cylinders. In Fig. 3 we haveillustrated one form of exterior valve mechanism shown and, describedand claimed in our former application for Letters Patent, filed N ov.'71927, Serial No. 231,724, the specific construction of which thereforeforms no part of ourpresent invention and will only .be sufficientlydescribed to enable our present invention to be understood.

The valve mechanism shown comprises a hollow casing, 6, provided with adiaphragm,

48, the central portion of which is connected with a valve actuatingpart, 20, which is connected by a link, 82, with an operator operatedpart, i. e., a foot lever, 80, provided with the usual retractingspring, 81. rI`he casing, 6, is connected by a link rod, 78, with 4 anarm, 78a, on the rock shaft, 7 6, connected with the brake mechanismsfor the nonsteering wheels of the tractor. The rear portion of the valvecasing,'6, is provided intevnavigate riorly with an annular seat, 11,normally engaged by the diaphragm and dividing the rear portion of thecasing into a central chamber, 13, from which a flexible pipe, 14,extends tothe actuator cylinder and an outer chamber, 12, connected by aflexible pipe, 32, to the suction passage of the engine between thethrottle valve and the engine cylinders, and being` preferably connectedto the intake manifold, 61. The front portion of the vvalve casingcommunicates with the atmosphere by apertures so that the front face ofthe dia-l phragm is always exposed to atmospheric pressure, and thediaphragm is providedwith apertures, 19, therein as shown. In'the rear.of the diaphragm isfa disk or valve, 10, having an annular seat, 10a,to engage the diaphragm and seal the casing in rear of the diaphragmfrom the atmosphere. The disc valve, 10, is normally in open positionwhen the` valve mechanism is in the released position as shown in yFig.3, so that the atmospheric air can pass through the apertures, 19, andthrough pipe, 14, to the actuator as hereinafter explained, thedifferential of presmechanism is in released position.

sures on the portions of the diaphragm be\ tween the annular seat, 11,and the outer edge of the casing, 6, assisting the retracting spring,81, in holding the diaphragm, 8, seated on seat,.11, thus cutting 0E theactuator from the suction pipe, 32, whenl the valve As will be seen, aforward movement of the pedal lever will seat the disc valve, 10, on thediaphragm, and will then unseat the diaphragm from the seat,y l1,connecting the cylinder with the suction pipe, 32, after disconnectingit from the atmosphere. Afterthe brakes have been applied to the fullextentof the power of the actuator, afurther depression of the footlever will bring the collar, 9, on the part, 20, into engagement withthe forward wall of the casing and enable the operator to apply hisphysical force through the valve casing and link rod, 78,'to the brakemecha-v nism only for the non-steering wheels, indicated at D, D. Itwill also be seen that when the valve mechanism is moved into'V positionto connect the actuator with suction, the forward face of the valve andthat portion of the forward face of the diaphragm between .the Valveseat and the casing will be exposed to atmospheric pressure, while thecorresponding portions of sure which he must exert on the pedal to keepthe' valve in this position, the amount of power which the actuator isexerting o the brake mechanisms.

Between the4 controlling valve mechanism and the actuator cylinder orcylinders, we

'locate' a pressure regulating valve or valves,

indicated as a Whole'at P, one, form of which is illustrated, ,forexample, in section in Fig. 2. Where several power actuators areemployed to operate different sets of brake mechanisms under thecontrol, of 'a single valve mechanism, one of thesevpressure regulatingvalves may be employed for varying the maximumdifferential of pressuresfor all of the actuators, but where the brake mechanisms operated bydifferent power actuators are subjected to different load conditions, aswhere diiferent actuators operate the steering wheel brake mechanismsand non-steer ing wheel brake mechanisms of a single vehicle, forexample, or Where as illustrated in y Fig. 1, the separate actuatorsoperate brake mechanisms on separate vehicles, as a tractor and trailer,we prefer to 'employ one of these pressure regulatingvalves between thecontrol valve mechanism and eachof said actuators,.1n order that themaximum differentlal of fluid pressures available for the operationapertures, 32, in communication with the at-l l mosphere, and acentrally located guiding aperture, 33. lVithin the casing is apartition member, indicated at 34, which in this instance is annular,the partition member dividing the interior of the valve casing into twochambers, in this instance a central chamber, 34a, and an. outer annularchamber, 35. The inner end of the partition member, 34, is provided witha seat, 34", in this instance an annular seat for engaging a exiblediaphragm, 36, having its outer edge portion in sealing engagement withthe valve casing and preferably clamped, as shown, between the casingand the cap or cover, 31. The diaphragm, 36,may be reinforced by acentrally located portion, indicated at .37, the area of which may besuilicient, as shown, to provide the seat engaging portions of thediaphragm, and this will be especially desirable where the diaphragm ismade of material such as rubberized or impregnated fabric, or othermaterial which would not readily make an air-tight connection whenpressed against the seat, 341.

While air lis being exhausted from the actuator, the diaphragm isyieldingly held in an unseated position against a predetermined degreeof rarification on its inner face, preferably by means of a springprovided with calibrating adjustment means and with a lao hand operatedtension regulating meansfor varying the tension of the spring inaccordance with the maximum degree of rariication desired for theoperation of the power actuator.

In Fig. 2 for example, we' have shown the diaphragm, 36, and itsreinforcing portion, 37, provided with a stem, 39, extending through theguiding aperture, 33, in the cover, and through a coaxial aperture in arotatable cam disc, 40, and through a corresponding aperture in aspring, 41, here shown in the form of a spider, the stem, 39, beingthreaded at its outer end, provided with an adjusting nut, 42, forCalibrating the'spring, 41. The

' cap or cover, 31, is provided in this instance,

with an annular plate, 43, provided with segmental cam grades, 43a, toengage corresponding segmental cam grades, 40a, on the cam disc, 40, ina well known way, to enable the tension of the spring, 41, which islocated between the adjusting nut, 42, and the cam disc, `40, to beadjusted by rotating the cam disc, 40, with respect to the stationaryplate, 43, in a well known way. The rotary cam disc, 40, is providedwith a hand lever, 40", or other operating means for rotating it, andthe stationary cam plate, 43, is preferably provided with an indexplate, 43h, upon which are provided indications for different positionsto which the arm or lever, 40, maybe moved to vaiy the tension of thespring, and thereby vary the maximum differential of fluid pressuresavailable to the actuator (or actuators) controlled thereby inaccordance with t e variations of the coefficient of friction be tweenthe wheels of the vehicle and the roadway. These indications willpreferably be such as to indicate the character of the road or the loadcondition, Qr both, for the differ-I ent settings or positions of theadjusting arm or lever, 401. For example, the index plate, 43", mayconveniently carry the following indilpations: Dry, Wet, Ice, Loaded,Medium,

ig t.

These rindications are only given by way of example and the indicationsplaced on the indicator plate, 43", or otherwise provided in connectionwith the movable hand operated adjusting part, may be of any desirednumber and of any character preferred, it being understood that theywill be so located that when theconditions expressed by any set ofindications present themselves, the movement of the hand operated leverto bring it into coincidence with such indications will so adjust thespring connected with the flexible diaphragm a'sto provide a maximumdifferential of fiuid pressure for the connected actuator or actuators,which will ordinarily prevent locking the wheels by the maximum power ofthe actuator under the conditions indicated. We do not limit 'ourselvesto the exact constructions shown, but we have found that they lprovide aconvenient and satisleading factory means for accomplishing the desiredresults, the adjusting nut, 42, serving to calibrate the spring, and therotary cam plate, `40, serving to effect the desired variations in thetension of the spring so calibrated to meet the diiferentconditions forwhich the device is intended. s

The pressure regulating valve is locatedv preferably on or in connectionwith the dash or instrument board, so that the hand operatedl lever,40", is within convenient reach of the driver of the vehicle, and itwill be understood that in the construction shown in Fig. 2 in which therotary cam plate adjusting means is employed, the parts will remain inposition to which they may be moved by the movement of the arm or lever,40", to secure the desired tension of the spring, 41.

The pressure regulating valve is interposed in the pipe, 14, previouslyreferred to, extending from the chamber, 13, of the controlling valvemechanism to the power actuator, or actuators, one of the chambers, 34aand 35, of the pressure regulating valve mechanism being connected tothe valve mechanism, and the other to the actuator, or actuators. Inthis instance we have shown the central chamber, 34a, connected directlywith the pipe, 14,

to the valve mechanism and the chamber, 35, connected by a pipe,indicated at 14, to the .actuator cylinder, 1. Where, as in Fig. 1, wehave a second brake mechanism provided with a separateactuator,.comprising in this instance a cylinder, 101, open at one endand closed at the other, and provided with a piston, 103, connected withan actuating arm, 7 7b, on the rock shaft, 76h, for actuating thebrakes, we prefer to provide a second pressure regulating valve,indicated as a whole at P1, which is connected to the controlling valvemechanism by a branch-pipe, 141. connected with the pipe, 14,independently'of the previously mentioned pressure regulating valve, P,and connected by a pipe, 14C, with the closed end of the cylinder, 101,a flexible portion, 14d, being conveniently arranged between thevehicles to accommodate relative movements thereof where the brakemechanisms are on separate vehicles. It will be understood that thepressure .regulating valve, P1, is constructed in the same manner aspreviously described with reference to Fig. 2 and that itis, connectedin the pipe line in the same manner, as previously de- -scr1bed. We alsoprefer in such case to provide a cut-off valve, 14", in the branch pipe,14h, which can be closed when the trailer is disconnected from thetractor vehicle. I

Referring now to the operation ofthe pressure regulating valve, it willbe understood that if all of the parts of the brake system gre inreleased positions, as indicated in Fig.

7 position to connect to pipe, 14,- with the atmosphere as indicated inFig. 3 andk to shut the controlling valve mechanism being in i offcommunication between the pipe, 14, and

the source of suction, the'pipe, 14, will be filled with atmospheric airas will the chambers of the pressure regulating valve or valves and thediaphragm 36, of each pressure regulating valve will be held unseatedwith a yielding pressure depending upon ythe adtions over normally dryroadways, the adbers of pressure regulating valve, P1, and

justing arm, will be moved to a point on the indicator plate or scalecorresponding` with the dry and loaded indications, for example, therebyadjusting the spring to substantially its maximum tension. Assuming thatthe engine is in operation and the throttle valve, 64, is closed orpartly closed, there willbe a partial vacuumv in the suction pass! ageof the engine and thepipe, 32, leading to the controlling Valvemechanism. If the op erator now` depresses the foot lever, 80, so as' toclose oli the atmosphere fromthe pipe, 14,

and connect it withv the Suction pipe, 32, as l g before described, theair will 'be withdrawn from the-pipe, 14, the chambers 34a and 35 of thepressure regulating valve P, the, pipe, 14a, and the cylinder, 1, oftheactuator and in like manner from the corresponding champipescommunicating with the cylinder, 101, on the trailer, thus 4causing anoperation of each actuator to apply the brake mechanisms connectedtherewith. A differential of iuid pressures will be created on theopposite faces `of the diaphragms, 36, of the pressure regulating valvesP and P1, dueto the rariiication within the valve c asing and atmospherepressure on the exter1or` face of the diaphragm.

- As the spring member, 41, of each pressure regulating valve has beenadjusted to its maximum tension, the diaphragm, 36, will be heldunseated and the full rarification in the sucwill be applied to eachvehicle with the maxition passageof the engine willbe available toeachof the poweractuators -andthe brakes mum pressure without, however,locking any of the wheels. If greater braking pressure is desired, as inmaking an emergency stop or otherwise, the operator, by taking up thelost motion between the valve actuating part, 20, inthe valve casing,may apply his physical force through the 'valve' mechanism and in this'instance, link rod, 78, .and arm, 78, to

connected brake mechanisms, in this instance the 'brakes of the wheels,D, D.

Let it be supposed, however, that the vehicle or vehicles enterA upon aportion of the roadway which is wet Iand slippery, whereobviously themaximum power ofthe actuavtorswould be sufficient to lock the/wheels,

, the operator will'instantly shift the adjusting lever, 40h, forexample, torelieve the tension Aof the spring, 41, .to the desiredextent, as indicated on the scale or-indicating plateby the word Wet. Insuch case if the controlling valve mechanism is operated to connect theactuators with the suction passage of the engine in the mannerpreviously described, the diaphragm will beheld of the seat by a reducedspring pressure, and as soon as the chamber, 34a, of either ofthepressure reglilating valves has been exhausted so as to produce adierential of fluid pressures on the diaphragm, 36, thereof, suficientto overcome the reduced spring resistance, the diaphragm will close andprevent further evacuation of the actuator cylinders,

so that the brake mechanisms can only be applied with a reduced maximumdifferential of fluid pressure determined by the adjustment of theresistance. spring of the pres- 41, of each pressure regulating device,therefore, within this range of varlations, the deree of suction orrarication which can be produced in the power actuator cylinderconnection therewith, and thereforethe maximum differential of iiuidpressures 'available to the actuators can be regulated as desired. Itwill be understood that when the foot lever is released and the pipe,14, is restored to its connection with the atmosphere, the air 'will ,beadmitted to the chambers, 34, of the fluid pressure regulating valves,equalizing the pressures therein until the diaphragm is retracted by thespring resistance into un-` seated position and allowing the air to flowinto the connected actuator cylinder or cylinders to release the brakemechanisms operated thereby. Where as in lating valves P and P'1 areemployed for i'ndependently regulating the maximum differential of fluidpressures available for operating the power actuator for the tractorbrake mechanism and the power actuator for the trailer brake mechanism,this. will be found particularly convenient to meet conditions arisingwhere one vehicle is more heavily loaded, for example, than the other,as it enables the maximum poyver which may be applied to the brakes ofeither vehicle to be independently controlled underl varying road andload conditions, so that the maximum power which shallibe available canFig. l, separatepressure regu- -K f under the varying condition-sstated.

It will be understood that under all conditions of operation and underall adjust-v l ments of the pressure regulating valve or valves theoperator may apply his physical force throughs-the pedal lever tocertain of thebrake mechanismsless than the whole number and preferablythe brake mechanisms for the non-steering wheels of the tractor vehicleas shown in Fig. 1 .in addition to the power of the actuator connectedtherewith and such brake mechanisms may also be applied by physicalforce alone in case of failure of power. Furthermore where alcontrollingvalve mechanism of the kind illustrated in Fig. 3, is employed theoperator will under all the variations in the available differential-orm of pressure regulating device in which the parts corresponding tothose illustrated in Fig. 2 are given the same reference numerals withthe addition of 100 to avoid repetition. In this ligure the valvecasing, 130, as shown is provided with a segmental partition, 134,extending across the interior of the casing, and provided with a seat,134", at its upper edge seat partition dividing the interior of thecasing into two chambers, 134 and 135, one of which, as 134, isconnected with the controlling valve mechanism by the pipe, 114, andtheother chamber, 135, is connected by pipe, 1.146, with the cylinder lofthe actuator. The other parts shown are exactly the same as previouslydescribed with reference to Fig. 2 and the operation-will be the same asthat previously described.

In Fig. 1 we have shown our invention applied to a braking system inwhich the power actuators have their pistons subjected to atmosphericpressure on both faces when the brake mechanisms and controlling valvemechanism are in released position. Our invention is equally applicableto brake systems in which the piston or pistons of the power actuator oractuators isor are subjected to,

suction on both faces when in the released position. In the former case.the brakes are applied by withdrawing air from the actuator cylinderforward of the piston and are released by again admitting air theretoand the pressure regulating valve is interposed between the controllingvalve and the pipe leading therefrom to the `forward end of thecylinder. In the latter case both ends of they actuator cylinder areclosed, the forward end 1S at all times connected with thesuctionpassage, and the brakes are applied by admitting air to the actuatorcylinder in rear of the pistons, and are released by withdrawing 1ttherefrom. In this case, therefore, it -is necessary to insert apressure regulating valve which limits the maximum degree of lower iuidpressure in the connecting pipe or passage between the source of suctionand 'Y the-*forward end of theftylinder, in order to vary thepowerbraking orce by controlling VYtrailer similar' to that illustratedin Fig. 1,

except that the power actuators are so arranged and constructed thattheir pistons are normally submerged in vacuum, when in releasedposition. The parts shown in Fig. 5 which correspond with those in Fig.1 have been given the same reference numerals with the addition of 200to avoid repetition, and in Fig. 6 We have illustrated a slightlymodiied form of valve mechanism also covered by our former application,Serial No. 231,7 24, which may be conveniently employed for controllingthe type of actuator illustrated in Fig. 5, although we do not limitourselves to this form of valve mechanism.

The controlling valve mechanism illustrated in Fig. 6 comprises acasing, 206, provided with a diaphragm valve, 208, adapted to engage anannular seat, 211, which divides the portion of the casing on one side,of the diaphragm into a central chamber, 213, and an annular suctionchamber, 212, the diaphragm being provided with apertures, 219, inalignment with the suction chamber, 212, for placing the portion, 214,of thefcasing, on the opposite side of the diaphragm at all times incommunication with the suction chamber, whether the diaphragm is seatedor unseated. Within the chamber, 213, of the valve casing is a cupshapeddisc valve, 210, having an annular Hange or seat, 210% for engaging thediaphragm, so as to make an airtight connection therewith, the discvalve and the diaphragm being rigidly and sealingly connected with ahollow sleeve, 220, extending through an aperture in the valve casing,and provided with an inlet aperture,

218, for air or other higher pressure liuid,A

outside of the said casing, and a communicating aperture, 2183, withinthe space between the disc valve andthe diaphragm. In this instance thevalve casing is connected by a link rod, -282, with the operatoroperated part, to wit, a foot lever, 280, provided with the'usualretracting spring, 281, and the valve actuating sleeve, 220, isconnected by a link rod, 27,8, with an arm,.278a, on'the rock shaft,276, connected with the brake mechanisms for the non-steering wheels ofthe tractor vehicle, indicated at A1 in Fig. 5. In the normal orreleased position of the valve mechanism which is shown in Fig. 6, thediaphragm valve is in engagement with the disc valve and is held therebyout of engagement with the seat, 211, the valve casing being providedpreferably within the chamber, 214, with an annular abutment, 206?, inalignment with the flange, 210, of the disc valve, to facilitate theseatin of the latter upon the diaphragm, and this a utment is providedwith transverse apertures, .indicated at 206C, so that the entire' withthe valve mechanism through the rod,

278, in this instance the non-steering wheel brake mechanisms of thetractor vehicle.

Y The valve casing is provided with an aperture, 21221, which is adaptedto be connected to the source of suction, in this instance they intakemanifold, 261, of the internal combustion engine for propelling thevehicle. The valve casing is also provided with an aperture, 213,adapted to be connected with one of the actuators in rear of the pistonthereof, and also with a similar aperture, indicated in dotted lines at213", ,adapted to be connected to the other actuator cylinder in rear ofthe piston. Obviously any number of actuators could be connected to thevalve casingifor simultaneous control.

201 represents the cylinder of the main actuator on the tractor vehicle,indicated by the dotted line, A1, which cylinder is closed at both endsand provided with a piston, 203, the piston rod of which is connected tovan l arm, 2774, on the rock shaft, 2,76, for o erating the non-steeringwheel brake mec y the pistons, 203 and 303, being lmaintained anisms,D1, of the tractor'vehicle. V177e have shown the cylinder, 201, movablelongitudinally with respect to the cylinder, like the cylinder, 1, inFig 1, andv pivotally supported on arms, 277, secured to the r'oc shaft,y2,7 6, which isconnected with the brake mechanisms, C1, for the frontor steering wheels of the tractor vehicle, as in Fig. 1. 301 representsthe cylinder of the auxiliary power actuator on the trailing vehicle,indicated by4 dotted. lines at B1, said cylinder'being also closed atboth ends and provided with a piston, 303, the piston rod of which isconnected with an arm, 277", operatively connected with the brakemechanisms, El, for the trailer. 1n this instance we have shown the mainsuction pipe, 232, connected with the intake manifold, 261, and providedwith a branch pipe, 232, which is connected to the aperture, 2123, ofthe controlling valve mechanism, communicating with 'the suctionchamber, 212, thereof. The main suction pipe, 232, is also provided witha branch pipe,

"f 232D, which is connected with the cylinder,

201, forward of thepiston therein. pressure regulating valve, indicatedat P2, and constructed and operating as hereinbefore described andillustrated for example in Fig. 2,*b'eing inserted in this branchsuction pipe,

from the main suction pipe, 232, to the cylinder, 301, onthe trailer,B1, and is provided with a flexible portion, 232, extending from onevehicle to the other. This branch suction pipe, 232, is also providedwith an independent pressure regulating valve, indicated at P3, andconstructed and operating as previously described and'illustratedforexample in Fig. 2. The main suction pipe is also shown provided with .acut-off valve' indicated at 232, located in this instance between thepressure regulating valves, P2 and P3, for cutting off/the branchsuction pipe, v

232, when the trailer is not in use.

` One of the apertures communicating with the chamber, 213, of the valvemechanism, as

the aperture, 213",`is connected bya pipe, 214, with the main cylinderin rear of the piston therein, and the other of said apertures, as theapertura-2133, is connected with the corresponding end of the auxiliarycylinder, 301, by Va pipe, 214% provided with a flexible portion, 2141,between the vehicles. It will be noted that when the Valve mechanism isin the released is shown in Fig. 6, t e pipes, 214ia and 2,14, are incommunication with the chamber, 213, and with the vacuum chamber, 212,and

' the branch suction pipe, 232% osition invwhlich it When thecontrolling valve mechanism,`

20'6, is in the released position and the pres `sure regulating valveisset for maximum rarification and the engine is running, both ends ofthe actuator cylinders, 201 and 301, will be connected with the intakemanifold,

normally submerged' in vacuum. lt will also be seen that the pipeconnections, 232b and 2321, leading from the main suction pipe, 232, tothe respective actuator cylinders forward of the pistons therein, whichare at `all times in communication with the intake manifold, may beindependently controlled by the pressure regulating valves, P2 and P3,lTo apply the brake mechanism the operator will depress the pedal, 280,thereby moving the valve casing, 206, in the direction of the arrowlwith respect to the valve actuating sleeve, 220, permitting thediaphragm, 208, to seat on the seat, 211, and the disc valve, 210, to bethereafter unseated from the diaphragm, cutting 0H the portion of eachactuator cylinder in rear of thepiston from the 'suction passage ef theengine and admitting atmospheric air or other higher pressure fluid tosaid portion of said cylinders, to effect a power stroke of eachactuater to apply all brakemechanisms connected therewith. As thedifferential of 4fluid pressures upon each actuator pistonis determinedby lthe differences between the substantially coningto each actuatorcylinder forward .of the piston therein to control the maximum degree fthe brakes.

I mitting the brakes to be released by their retracting means. lVhen thebrakes and connected parts are lefty in the off or released position forlong periods of time, and theI pressure regulating valve mechanism isset for less than the maximum degree of rarification, leakage may occurpast the piston and the cylinder becomes submerged in the maX- imumdegree of rarification. This will not materially effect the applicationof the brakes -as the maximum vacuum obtained from the intake manifoldof an internal combustion engine is approximately 20 inches of mer-'that for which the cury, and therefore a forward movement of the pistonto apply the brakes would nor,- mally result in a kdecrease inraricationwithin the cylinder forward of the piston below the control range of thepressure regulating valve. In other words, some air must be exhaustedfrom the cylinder forward of the piston, and if the pressure regulatingvalve is firmly seated, this air remaining withinl the cylinder forwardof the piston will cause a reduction in the degree of rarilication untilthe degree of rarilication equals pressure regulating valve isset. vItis true this may not be the case where the actuator cylinder is muchlonger than the operative Istroke of the piston, in which case theportion of the cylinder for- .ward of the piston virtually constitutes astorage reservoir, and ifa storage reservoir is used, it may benecessary to insert a pressure regulating valve in the pipe, 232, asindicated at P4 in Fig. 5a. It will be understood that the size of thepower actuators or their connection Awith the brake mechanisms is suchthat the wheels of the vehicle will not be locked on the averagedrypavement when the vehicle is fully loaded, even when the pressureregulating valve is set for maximum vacuum. If greater braking force isnecessary or desired, the operator can take up the lost motion betweenthe disc valve, 210, and the valve casing, 206, and apply his physicalforce through the arm, 278, to the brake mechanisms connected therewith,in this instance the brake mechanisms for the rear wheels. To releasethe brake mechanisms it is only necessary to release the pressure on thefoot pedal to effect the 'unseating ofl the 'i diaphragm, 208,v whichfwill again connect --each actuator cylinder in rear of lits piston withtheactuator on the other side of the piston and with the suctionpassage, equalizing pressures within the cylinder or cylinders andwithdrawing the air previously admitted, and permitting the brakes to beinstantly released and to be retracted by their retracting springs,which also return the pistons to normal position. It will be furtherunderstood that by adjusting the pressure regulating valves, P2 and P3,the available degree of rarification for the power stroke of eachactuator can be regulated according to the frictional contact betweenthe wheels and the roadway, to vary the power which lcan be applied tothe brakes, so that they may be applied to the maximum by thecontrolling valve mechanism without locking the wheels and causingskidding, and it will also be seen that these valves may beindependently adjusted to secure the desired available maX- imuinbraking power for the tractor and trailer respectively, under varyingconditions' of load, as previously explained with reference to Figs. lto 3.

t will be understood that the construction and operation of the pressureregulating valves', P2 and P3, in this embodiment of our invention, willbe the same as previously described with reference to the embodimentshown in the preceding figures. V

As shown in Figs. 5 and 5a, a check valve, 232", may be inserted in thesuction pipe, 232,

vbetween the suction passage'of the engine and the connections to thepressure regulating and controlling valve mechanisms for the purpose ofmaintaining the maximum raritication available, within the cylinder atall times, so that the brakes 4may be applied or held as applied shouldthe motor stop. The check valve, as located, will permit the brakes tobe released by equalization of pressures within the cylinder orcylinders'even though there should be no suction available to withdrawthe air admitted yfor an appli cation of the brakes, as for example whenthe motor stalls.

What we claim and desire to secure by Letters Patent is 1. In a brakesystem for automotive vehicles provided with aninternal combustionengine for propelling the same, having a throttle controlled suctionpassage, the combination with a plurality of power actuators, brakemechanisms operatively connected with each actuator, a singlecontrolling valve mechanism for said actuators, connectlons forconnecting said suction passage with said valve mechanism and with .eachof said actu# ators, and means for connecting said valve mechanism witha source of higher pressure fluid of substantially uniform pressure, ofan independent pressure regulating valve in each portion o f theaforementioned connecloperation thereof, vwhereby said actuators ILevanto may be substantially,simultaneously operated to apply a maximumpower as to each, determined by the pressure regulating valve therefor,to the brake mechanismsconnectyed therewith. f

2. In a brake system for automotive vehicles provided with an internalcombustion engine for propelling the same, having a throttle controlledsuction assage, the com` bination with a plurality o power actuators,brake mechanisms operatively connected with each. actuator, a singlecontrolling valve mechanism for said actuators, connections forconnecting said suction passage with said valve mechanism and with eachof said actuators, and means for connectin said valve mechanism with asource of hig er pressure fluid of substantiallyuniform pressure, of

an independent regulating valve in each portion of the aforementionedconnections interconnecting the suction passage of the en gine andeach'actuator, for regulating the degree of rarification available forthe operation thereof, independent means for adjusting each of saidpressure regulating valves, and an operator operated part connected withsaid controlling valve mechanism, whereby said. actuators maybepsubstantially simultaneously operated to apply a maximum power as toeach, determined by the pressure regulating valve therefor, to the brakemechanisms connected therewith.

3. In a brake system for automotive vehicles provided with an intern-alcombustion engine for propelling the same, having a throttle controlledsuction-passage, the combination with a plurality of power actuators,each comprising a cylinder `and a piston therein, brake mechanismsoperatively connected with each of said pistons, a single controllingvalve mechanism for said actuators,

' connections for connecting said suction Ipassage with said valvemechanism and with each of saidactuators forward ofthe piston thereof,and means for connecting saidvalve mechanism with a source of higherpressure fluid of substantially uniform pressure, of an independentpressure regulating valve in each portion of the aforementionedconnections interconnecting the suction passage of the en; gine and v.each actuator cylinder forward of the piston, for regulating the degreeof rarication available for the operat1on'thereof, and an operatoroperated part connected with' said controlling valve` mechanism, wherebysaid actuators maybefsubstantially simultaneously operated to apply amaximum power as to each, determinedby the pressure regulating valvetherefor, to the brake mechanisms connected therewith.

4. In a brake system for automotive vehicles providedwith an internalcombustion engine for propelling the same, having a throttle 'controlledsuction assage, the combination with a plurality o power actuators, g

-each comprising a cylinder and a piston therein, brake mechanismsoperatively connected with each of said pistons, a single controlling`valve mechanism for 'said actuators, connections for connecting saidsuction passage with said valve mechanismand with each of said actuatorsforward' ofthe piston thereof, and means for connecting said va'lvemechanism with a source of higher pressure fluid of substantiallyuniform presnism, whereby said actuators may be' substantiallysimultaneously operated to applyl a maximum power as to each, determinedby the pressure regulating valve therefor, to the'brake mechanismsconnected therewith. 5. In a brake system for automotive ve hiclesprovided with an internal combustiony engine for propelling the same,having a throttle controlled suction passage, the combination with aplurality of power actuators,

Y each comprising a cylinder and a piston therein, brake mechanismsoperatively connected l with each of said pistons, a single controllingvalve mechanism for saidactuators, connections for connectlng saidsuction passage wlth sald valve mechanism and w1th each of sald actuatorcylinders forward of the ,piston thereof, independently .of said valvemechanism, means for connecting said valve mech-v anism with each ofsaid cylinders in rear of the piston thereof, means for connecting saidv valve mechanism with a source ofhigher pressure fluid ofsubstatially'uniform pres- I sure, of an independent pressure regulatingvalve in each portion of the aforementioned connections interconnectingthe suction'passage of the engine and each actuator cylinder forward ofthe piston thereof, for regulating thedegree of rariiication'availablefor the operation thereof, and an operator. operated partfconnfectedwithl said controlling valve mechanism, whereby said actuators may bel fply a maximum power as to each, determined by the pressure regulatingvalve therefor, to the brake mechanisms connected therewlth..

6. In a brake system for automotive vehicles provided with an internalcombgstion engine for propelling the same, having a throttle controlledsuction passage, the comhination with a plurality of power actuators,

therein, brake mechanisms operatively connected with each of saidpistons, a. single gong-1,?

trolling valve mechanism for said actuators,

v'substantially simultaneously operated to app each comprising acylinder and 'a piston y rear of the piston thereof, means forconnecting said valve1 mechanism with asource of hlgher pressure fluidof substantially unij form pressure, of an independent pressure valve ineach portion of the aforeregulatin d connections interconnecting thementione suction passage of the engine and each actuator cylinderforward of the piston thereof,

for` re ulating the degree of rarification availab e for the operationthereof, inde` pendent means for adjusting each of said pressureregulating valves, and 'an operator operated part connected withsaidcontrolling valve mechanism, whereby said` actuators may besubstantially simultaneously operated to ap ly a maximum power as toeach, determined y. the pressure regulating valve therefor, to the brakemechanisms connected therewith. y

. 7. In a brake system for automotive vehicles including a tractor andtrailer, provided with an internal combustionl engine located on thetractor for propelling the vehicles, and having a throttle controlledsuction passage, the combination with a power actuator located on thetractor and opera- \tively connected with "brake mechanisms termined bytherefor, a power actuator located on the trailer and operativelyconnected with brake mechanisms therefor, ansingle controlling valvemechanism for substantially ysimultaneously operating said actuators toapply the brake mechanisms of both vehicles, connections for connectingsaidr suction passage with said valve mechanism and with each of saidactuators, means for connecting said valve mechanism with a source ofhigher pressure fluid of substantially uniform pressure, of anindependent pressure regulating valve in each portion of theaforementioned connections interconnecting the suction passage oftheengine and each actuator, for regulating the degree of rarificationavailable for the operation thereof, and an operator operated part onthe tractor connected with said controlling valve mechanism, whereby thebrake mechanisms of both tractor and trailer may be substantiallysimultaneously' applied to a maximum .extentas to eacl1,\ detherefor. yv

L8. In a brake system for automotive vehicles including a tractor andtrailer, provided with an internal combustion engine located on thetractor for propelling the vehicles, and having a throttle controlledsuc# tion passage, the combination with a power actuator located on thetractor and opera- 'tively connected with brake mechanisms the pressureregulating valve with said valve mechanism and with each of y said`actuators, means for connecting said valve mechanism with a source ofhigher pressure fluid of substantially uniform pressure, of an'independent pressure regulating valve in each portion of theaforementioned connections interconnecting the suction passage of theengine and each actuator, for

able for t e operation thereof, said pressure regulating valvesbeinglocated on the tractor, independent means for adjusting each ofsaid pressure regulating valves, and an operator operated part on thetractor connected with said controlling valve mechanism, whereby thebrake mechanisms of each vehicle may be substantially simultaneouslyapplied to a maximum extent determined by the pressure regulating valvefor the actuator connected therewith. i 9. In a brake system for'automotive vehicles provided with an internal combustion Lengine forpropelling the same, havingfa `throttle controlled suctionpassage, thecombination with a plurality of power actuators, brake mechanismsoperatively connected with each actuator, a single controlling valve ymechanism for said actuators, connections for connecting such suctionpassage w1th said valvemechanism and with each of said actuators, andmeans for connecting said valve mechanism with a lsource of higherpressurev fluid of substantially uniform pressure, of an independentpressure regulating Valve in each portion of the aforementionedregulatingl the degree of rarification avail# connectionsinterconnecting the suction passage of the engine and Deach actuator,for regulating the degree of rariication available for the operationthereof, whereby said actuators may be substantially simultaneouslyoperated to apply a maximum power as to each, determined by the pressureregulating valve therefor, to the brake mechanisms connected therewith,said operator operated part being connected to certain of said brakemech# anisms less than the whole number, for'jenabling the operator tbapply his physicalA force thereto. v j

10. In a brake system for automotive vehicles including a tractor andtrailer, provided with an internal combustion engine located on thetractor for propelling the vehicles, and having a throttle controlledsuction passage','the combination with a power actuator located on thetractor and operatively -connected a with brake mechanisms therefor, apower actuatorv located on the trailer and operatively connected withbrake i said actuators, means forv connecting said valve mechanism witha source of higher pressure luidof substantially uniform pressure, of anindependent pressure regulating valve in'each portion of theaforementioned connections interconnecting the suction passage of theengine and each actuator, for regulating the degree of rarificatienavailable for the operation thereof, said pressure regulating valvesbeing located on the tractor, independent means for adjusting each ofsaid pressure regulating-valves, and an operator operated part on thetractor connected with `said controlling valve mechanism, .whereby thebrake mechanisms of each vehicle may be 4substantially simultaneouslyapplied to a maximum extent determined by the pressure regulating valvefor the actuator connected therewith, said operator operated part beingconnected with certain of the brake mechanisms forthe tractor, forenabling the operator to apply his physical force thereto.

11. In a brake system for'automotive vehicles including a tractor andtrailer, provided with an internal combustion engine located on thetractor for propelling the vehicles, and having a throttle controlled suction passage, the combination with a power actuator located on thetractor, independent brake mechanisms for steering wheelsN andnon-steering wheels of said tractor operatively connected to saidactuator, a second actuator located on the trailer, brake mechanisms forthe trailer connected therewith, a single controlling valve mechanism onthe tractor for said actuator, connections for connecting said suctionpassage with said valve mechanism and with each of said actuators, meansfor connecting said valve mechanism with a source of higher pressurefluid of s'ul'1 nected with each actuator, to a maximum ex stantiallyuniform pressure, of an independent pressure regulating valve in eachportion of the aforementioned connections interconnecting the suctionpassage of the engine and each actuator, independent means for adjustingeach of said pressure regulating valves, and an operator operated partlocated on the tractor, connected with said controllingvalve mechanism,for substantially simultaneously applying all .of the brake mechanismscontent determined by the pressure regulating .valves therefor, saidoperator operated part being connected with brake mechanisms fornon-steering vwheels only of the tractor, Ato

enable the operator to apply his physical force to said non-steeringwheel brake mechanisms.

12: h a'mbr'ake for autOmOtiVe Vie- Vof higher fluid pressure atsubstantially uniform pressure, a tubular connection from the portion ofthe'cylinder forward of the piston to said suction passage, independentofthe connection between said controlling valve mechanism andthesuctionpassage, and an operator operated' part for said valve mechainism, of a pressure regulating valve located in said independent tubularconnection and comprising a casing having separated chambers, oneconnected with said portions of they cylinder forward of the piston, andthe other chamber being connected with said suction passage, saidchambers being opened at their inner ends and provided with'seating,means, a pressure opera-ted part having marginal portions'in sealingengagement with said casing, and having its outer face subjected at alltimes to the pressure osaid higher pressure Huid in a direction to sea-tsaid part upon said seating means and disconnect said chambers from eachother, and yielding resistance means connected with said pressureoperating part andacting in a direction to unseat it, said pressureoperating part being seated when- 100 ever the differential of iuidpressures on its opposite faces is suliicient to overcome` said lresistance means, whereby a substantially constant maximum differentialof'lluid pressures is maintained available for the operation of v saidactuator.

13. In a brake system for automotive vehicles provided with an internalcombustion.

engine for propelling the vehicle, having a throttle controlled suctionpassage, the combination with brake mechanism, of a suction actuatedpower actuator comprising a cylinder closed at both ends, a piston insaid cylinder connected vwith said brake mechanism,v

controlling valve mechanism for connecting 11'5` lmechanism and thesuction passage, and an operator operated'pa'rt for said valve-mechanism, of a pressure regulating valve located in said independenttubular connectionand comprising a casing having separated chambers, oneconnected with said portions of the 'cylinder forward of thepiston, andthe other chamber being connected `with said Suction ing, and having itsouter face subjected at all i passage, said chambers being opened attheir inner ends and provided with seating means,

ai pressure operated part having' marginal- Iortions in sealingengagement with said castimes to the pressure ofl said higher pressurefluid in a direction to seat said part upon said J tures.

seating means and disconnect said chambers from each other, and yieldingresistance means connected with said pressure operating part and actingin a direction to unseat it, said pressure operating part being seatedWhenever the ,differential of fluid pressures on its opposite faces issucient to overcome said resistance means, whereby `a` substantiallyconstant maximum differential of Huid pressures is maintained availablefor the loperation of said actuator, and hand operated adjusting meansfor varying the maximum differential of fluid pressures available forthe operation of the actuator in-accordance v'vith variations in thecoeiicient of friction between the vehicle wheels and the roadway.

In testimony whereof We ax our signa- CALEB s. BRAGG. VICTOR W.KLIESRATH;

